Various software systems and application programs running on an operating system make extensive use of exit routines or routines that have exit routine like properties. Among these software systems and application programs are the IBM DB2 database running on the IBM Z/OS operating system, which makes extensive use of exit routines. IBM, DB2, and Z/OS are registered trademarks of the International Business Machines Corporation.
Such exit routines, may for example, be used to implement or enable application-transparent operations such as data encryption, as described in co-pending U.S. Utility patent application Ser. No. 11/704,705 filed 8 Feb. 2007 and entitled “High Performance Data Encryption Server and Method For Transparently Encrypting/Decrypting Data”; incorporated by reference herein and assigned to Ingrian Networks, Inc. (of Redwood City, Calif., USA), the same assignee as the present patent application. In this example, field exit routines or table exit routines are defined for database tables (such as IBM DB2 tables) which contain encrypted fields.
Although exit routines provide useful computer program constructs in some situations, these same exit routines become a problem when a bulk operation, for example an operation that involves all of (or even a large amount of) the data from the database table, or loading the entire contents of a database table at once, needs to be performed. A problem with the use of bulk operations on such database tables (including with IBM DB2 database tables) with exit routines arises because the exit routines are invoked every time a row or a column, depending on the type of exit, needs to be modified or accessed. Such access may typically be either through the use of an SQL statement or through a LOAD utility.
This problem imposes a potentially unacceptable performance overhead for loading data in bulk, migrating un-encrypted data (such as for example when transforming one or more fields from the table, designated for encryption, from non-encrypted to encrypted form in the entire table at once), and for re-encrypting the already encrypted data (such as for example, in order to change the encryption key for the entire table at once). It is well known in the art that bulk operations on large database tables performed on a single row at a time, lead to unacceptable performance and are rejected by the industry's best practices. There remains a need therefore for a system and method that provide means for implementing bulk operations on database tables with exit routines defined for operations on such tables.